Freezing of piping and faucets in external walls or poorly heated areas often results in ruptured plumbing, wasted water, and water damage to a building. A common solution is to crack the faucet open sufficiently to allow slow dripping. The flowing water is warm enough to prevent freezing of piping upstream of the faucet. In the event the piping should freeze anyway, the pressure of expanding ice is relieved. However, faucet dripping is not always feasible, as homeowners are not home, or forget, or a cold night is not expected. In addition, an air bleed should be provided to drain water from the faucet to further prevent freezing, and to preclude siphoning of dirty water back into the supply.
Faucets and hydrants which allow dripping of water and anti-siphon are known and, heretofore, have been configured in various ways. Some examples of such faucets are seen in the following U. S. Patents:
Chamberlin, U.S. Pat. No. 4,809,727, discloses a thermally contracting and expanding rod that opens and closes a valve to provide flow; PA1 Canterbury, U.S. Pat. No. 3,446,226, Nakajima, U.S. Pat No. 4,066,090, Rice, U.S. Pat. No. 4,296,770, Kolze, U.S. Pat. No. 4,460,006, Alderman, U.S. Pat. No. 4,484,594, Barrineau, U.S. Pat. No. 4,638,828, Chamberlin, U.S. Pat. No. 4,437,481, Carney, U.S. Pat. No. 4,784,173, Walters, U.S. Pat. No. 4,344,450, and Hucks, U.S. Pat. No. 4,205,698, employ thermally expanding or contracting fluids to actuate the drip valve at a predetermined temperature; PA1 Watanabe, U.S. Pat. No. 4,932,429, uses a shape-memory alloy to actuate the drip valve at a predetermined temperature; PA1 Lyons, U.S. Pat. No. 4,657,038, shows a thermally actuated electric switch that opens a solenoid operated valve to provide flow; PA1 Pike, U.S. Pat. No. 4,475,570, Enterante, Sr., et al, U.S. Pat. No. 4,909,270, Breneman, U.S. Pat. No. 4,821,762, Ackroyd, U.S. Pat. No. 5,129,416, Conway, U.S. Pat. No. 5,158,105, and Hunley, U.S. Pat. No. 4,971,097, illustrate a hydrant that admits air to displace and drain water after shutting off the valve.
None of the above-described devices combine both a thermally actuated drip valve with an anti-siphon feature. The prior art devices are subject to distortion and damage to the valve seating surfaces by excessive torque applied to the handle. Further damage to the seat and leakage is possible from misalignment of the seating surfaces. The thermal actuation of these devices is subject to time delay due to the thermal element being surrounded by layers of material and structure. This slows the heat transfer required for actuation, placing piping at risk during periods of plummeting temperatures.
Accordingly, there is a need to provide a faucet having both a thermally actuated drip valve so as not to freeze, and an anti-siphon bleed valve to avoid contaminating the water supply. There is a further need to provide a stop to limit damage to the valve seating surfaces by excessive torque applied to the handle. A yet further need is to provide self alignment of the seating surfaces to prevent damage to the seat and leakage. Another need is to provide a heat sink to conduct heat from the thermal actuator to the ambient air to shorten response time in the event of rapid temperature change.